DAQ Power Supply
Gammasphere's upgraded DAQ system has a redundant 48V supply in each of its four racks. It is on top of both the collector box and VME crate in each relay rack, and connects directly to an overhead cord reel. Each supply powers the collector box and up to 30 detectors. Its internal supplies have fault relays that are monitored by EPICS.
In terms of redundancy, one can choose to either leave one supply off as a cold spare, or switch on both the primary and backup supplies to provide a hot spare capability. Either way, the supplies each provide alarm status outputs that are connected to the collector box, which in turn makes the alarm status available for monitoring via the EPICS control system.
The supply outputs are natively floating, or in otherwards not referenced to ground, so that the grounding point of the system can be defined at the digitizer rather than the ground at the 48V DC supply. Note that each detector’s power supply is actually doubly isolated as the point-of-load SBX Power Supplies that are located on each detector additionally provide isolation between the 48V supply and the detector’s ground (and power). However, this supply’s metal chassis can be isolated from the relay rack’s metal frame to eliminate the possibility of a ground loop between the two power cord reels feeding each of the relay racks.
Gammasphere's power supply, unlike much of the hardware used within the DAQ system, is not designed or created by Argonne, and is from a manufacturer. The datasheet with the product specifications are on the DAQ Power Supply Datasheet.